Scientific performances evaluation of the Raman Laser (RLS) FM-instrument for Exomars mission to Mars

The Raman Laser Spectrometer (RLS) is part of the analytical payload located inside Rosalind Franklin rover for the Exomars Mission to Mars.

The RLS instrument consists of three main units: 1) the optical head that focus the laser excitation on the sample and collect the scattered light from the same area (with a 50 microns spot); 2) the spectrometer analyzing the Raman signal in the spectral range 150-3800 cm-1 with an average spectral resolution of 8 cm-1 and 3) an electronic control unit in which the laser is included.  These units are connected by optical fibers and electrical hardness. The instrument will investigate powdered samples collected by the rover at the surface and subsurface of Mars at the mineral grain scale. (1)

The RLS development stages comprised the development, verification, test and evaluation of the scientific performances of two main models: Engineering Qualification Model (EQM) and Flight Model (FM). 

Because the consecutive delays in Exomars launch to Mars an important aspect related with this situation is the evaluation of the scientific performances with time of these models comparing the results obtained at the pre-delivery stage with those obtained at the rover analytical laboratory drawer (ALD) and rover integrated stages.

Additionally it is also of great interest evaluate the scientific results obtained in the framework of dedicated science activities currently ongoing at the ALD and rover levels  in which the evaluation of the combined science potential among the three instruments inside Rosalind Franklin rover (MicrOmega, RLS and MOMA) is outstanding.

In the present work interest is devoted to the scientific performances evaluation of the RLS-FM at the different levels: pre-delivery, rover analytical drawer (ALD) and finally integrated on the Rosalind Franklin rover.

For that, observation of the data obtained on the calibration target (CT) is mainly used although data obtained on standard and natural samples at the pre-delivery stage are also presented and discussed.

Instrument response as function of temperature, atmospheric pressure conditions and changes on the main acquisition parameters was evaluated. Estimation of the different band parameters observed (band position, intensity, bandwidth and SNR) allowed performances comparison along the different phases of the process and comparison with the established scientific requirements.

References:

• Rull, S. Maurice, I. Hutchinson, A. Moral et al., Astrobiology, 2017, 17, 627-654.